Methods
Data Collection and Analysis
Data Collection and Analysis
Data was collected at 136 lakes located in 130 townships across the province of Alberta (Fig. 1) from 2009-2023, looking for the presence of blue-green algae20, with the variables measured indicated in Table 1. Each lake had a different number of samples taken and the presence of one organism counted as one cell count. Interpolated climate data was used for each township to determine the climatic conditions for the years from the Government of Alberta Interpolated Climate Data (https://acis.alberta.ca/township-data-viewer.jsp). Data was pooled based on the natural ecoregions in Alberta (Fig. 2) with the following climate variables averaged across the ecoregion: mean annual high temperature (°C) from May to October, mean annual low temperature (°C) from May to October, total precipitation (mm) received from May to October, and the total snow water equivalent (cm) from August to July21. Data was considered for temperature and precipitation from May to October as blue-green algae blooms occur during these periods and would be impacted by the weather during this period (see Fig. 9- data page). Snow water equivalent (SWE) was taken as the maximum amount calculated for the previous year (August to July), as this will be equivalent to the total amount of meltwater received that year and would potentially impact early blooms. Together, the climate data and blue-green algae samples will be taken on a daily timescale and averaged across the season.
Data was collected at 136 lakes located in 130 townships across the province of Alberta (Fig. 1) from 2009-2023, looking for the presence of blue-green algae20, with the variables measured indicated in Table 1. Each lake had a different number of samples taken and the presence of one organism counted as one cell count. Interpolated climate data was used for each township to determine the climatic conditions for the years from the Government of Alberta Interpolated Climate Data (https://acis.alberta.ca/township-data-viewer.jsp). Data was pooled based on the natural ecoregions in Alberta (Fig. 2) with the following climate variables averaged across the ecoregion: mean annual high temperature (°C) from May to October, mean annual low temperature (°C) from May to October, total precipitation (mm) received from May to October, and the total snow water equivalent (cm) from August to July21. Data was considered for temperature and precipitation from May to October as blue-green algae blooms occur during these periods and would be impacted by the weather during this period (see Fig. 9- data page). Snow water equivalent (SWE) was taken as the maximum amount calculated for the previous year (August to July), as this will be equivalent to the total amount of meltwater received that year and would potentially impact early blooms. Together, the climate data and blue-green algae samples will be taken on a daily timescale and averaged across the season.
Figure 1. Map of all sample locations in Alberta by township location21. A sampled township is indicated in black, with interpolated climate data determined by township location.
Figure 2. Map of Alberta natural ecoregions as of 200522. Townships considered fall within the Boreal (light green), Foothills (light blue), Grassland (yellow), and Parkland (orange).
Table 1. Description of the blue-green algae considered20.
Image 6. Cyanobacteria sp23.